The present invention relates to a soft magnetic material, in particular a metallic magnetic material suitable for use as the material of a magnetic head, and also to a magnetic head made of such a magnetic material.
Hitherto, a hard Fe--Si--Al type alloy known as sendust alloy has been used as a metallic magnetic material for use as the material of magnetic heads.
This metallic magnetic material has a high magnetic flux density saturation level but exhibits a large eddy current loss and, hence, a low magnetic permeability particularly at a high-frequency region due to too low electrical resistance. In addition, this material exhibits inferior wear resistance against abrasion by magnetic tape, as compared with ferrite-type magnetic heads made of oxide magnetic materials.
In order to obviate these problems encountered when this type of magnetic material is used as the material of a magnetic head, i.e., to reduce eddy current loss a in high-frequency range, a magnetic head called an "alloy laminated type magnetic head" has been proposed in which the metallic magnetic material is in a shape of thin film-type members stacked with an electrically insulating layer being interposed between adjacent one of the thin members.
An example of such an alloy laminated type magnetic head is a so-called sandwich type magnetic head which is produced by forming a thin alloy film on a substrate by a thin-film forming technique such as sputtering or evaporative deposition followed by formation of an intermediate insulation layer thereon, the thin alloy films and the insulation layers being formed alternatingly until a laminate of a predetermined thickness is formed, with the other substrate bonded by, for example, a glass bonding technique.
This known magnetic head having a laminated structure not only requires an expensive production apparatus such as a vacuum evaporation apparatus or a sputtering apparatus but requires an impractically long time due to a too small deposition speed. In fact, the deposition speed is as low as 500 .ANG./min or so even when a magnetron-type apparatus is used, when the quality of the film is strictly controlled. When a magnetic head having a track width of 50 microns is to be produced, it takes about 17 hours even for the formation of a single layer. The production time will be multiplied for laminating a plurality of such single layers.
Another problem encountered with the sandwich-type laminated magnetic head is that the substrates and the magnetic material exhibit different amounts of wear after the use of the magnetic head in contact with a running tape.
Thus, the magnetic material for use as a material of magnetic heads is required to have high levels of saturation magnetic flux density and electrical resistance.
There is also a demand for a laminated magnetic head which can be produced quickly and efficiently and at a low cost without requiring any expensive thin-film forming apparatus and which exhibits a high resistance to wear when used in contact with a running magnetic tape.